I've seen diamonds mate from anytime now through to mid october - depending on ambient temps and whether indoor or outdoor. Outdoor diamonds usually don't start to mate for another two weeks (but we have had a wierd winter) from my observations that is.
As for Bredli's, I have mine inside and their first witnessed mating was 18.08.06 at 1845 and lasted for over 4 hours

I have witnessed them locked on two other occassions since then. But only they know what goes on in that hide
Hope this helped.
Cheers
D. :wink: